Hello.

Is there any point uploading my 600 stock videos to YouTube? Someone said it will good for SEO. But then can be downloaded for free.

Depends what your purpose is.

If you are just bored, and have nothing better to do, then no - it is probably a waste of time.

However, if you have some kind of marketing/sales plan in mind, then potentially it could be worth it.

If you go ahead, make sure that you watermark those videos.